Guard for preventing inadvertent operation of electrical switches

ABSTRACT

A cylindrical guard device for electrical switches, the guard having a plurality of flattened areas on the outer surface at one end thereof. The switch mounting screws and additional guard mounting screws form a nest for the guard which is inserted with the flattened portions in registration with the screws. Rotation of the guard wedges the round portions of the guard against the screw threads to thereby secure it in position about the switch actuator.

United StatesvPatent 1 1 3,746,818

Bertelloti July 17, 1973 [54] gggggig: ggi 'gg gggxfig? FOREIGN PATENTS OR APPLICATIONS 772,277 4/1957 Great Britain 200/42 T [75] Inventor: Ansano Bertelloti, Addison, Ill.

[73] Assignee: GTE Automatic Electric P im ry Xa ine J- V. Truhe Laboratories Incorporated, Assistant Examinerwilliarn J. Smith Northlake, Ill. Attorney-K. Mullerheim, Robert F. Van Epps et al. [22] Filed: Oct. 4, 1972 S 57 B T 21 Appl. No.: 295,066 1 A RACT A cylindrical guard device for electrical switches, the

guard having a plurality of flattened areas on the outer [52] 200/168 200/42 200/169 PB surface at one end thereof. The switch mounting screws [51] Ill!- and additional guard mounting Screws form a nest for [58] held of Search 200/42 42 169 the guard which is inserted with the flattened portions 200/169 168 168 C in registration with the screws. Rotation of the guard [56] References Cited wedges the round portions of the guard against the screw threads to thereby secure it in position about the UNITED STATES PATENTS it h a tuator,

2,824,915 2/1958 Buturuga 200 42 T 2,813,938 11/1957 Speizman 200/42 T 4 Clams, 4 Drawmg Figures Pate n ted July 17, 1973 3,746,818

PRIOR ART BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to guards for preventing inadvertant operation of electrical switches and more particularly to a new and improved guard for push type switches.

2. Description of the Prior Art It is generally known that panel mounted electrical switches of many types are subject to inadvertant actuation. In the recognition of this problem, various safety guards intended for use with various specific types of switches have been described. Two examples of toggle type switch guards are disclosed in U.S. Pat. Nos. 3,170,050 and 3,527,914. A safety device for a rotary type switch is described in U.S. Pat. No. 3,847,526. Guards of the former type are typically assembled with their associated switches by means of screws or nuts and thus complicate the replacement of the switches or their service; e.g. replacement of a lens cap or lamp in a lighted switch. Other types of safety devices, such as that described in the latter referenced patent must be completely removed in order that the protected switch may be operated.

OBJECTS AND SUMMARY OF THE INVENTION From the preceding discussion it will be understood that among the various objectives of the present invention are included the following:

the provision of a new and improved guard for electrical switches;

the provision of a device of the above-described character of particular utility with push type switches;

the provision of a device of the above-described character which facilitates installation and removal thereof; and

the provision of a device of the above-described character which permits intentional operation of the switch with the guard in place.

These and other objectives of the present invention are efficiently achieved by providing a cylindrical tube which extends beyond the actuator of a panel mounted switch. A plurality of screws, at least two of which serve to mount the switch to the panel, extend from the face of the panel and are so positioned as to form a nest for the guard. The guard is provided with a plurality of flattened areas on its exterior surface adjacent one end of the cylinder which correspond to the positions of the screws. Rotation of the guard serves to wedge it against the screw threads thereby securing the guard in position about the switch actuator.

The foregoing as well as other objects, features and advantages of the present invention will become more apparent from the following detailed description when considered in conjunction with the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-section view of a panel-mounted push type switch of the prior art;

FIG. 2 is an elevation view of the switch of FIG. 1 provided with the guard of the present invention.

FIGS. 3A and 3B are top views of the arrangement of FIG. 2 illustrating the operation of the present inven- U".

DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to FIG. 1 there is schematically illustrated a conventional push type switch 10 which is typically mounted in a panel 12 by first and second mounting screws 14. It will be readily seen that the pushbutton actuator 16 of the switch is very susceptible to inadvertant actuation since it extends above the surface of the panel 12. The actuator 16 may or may not be removable from the front of the panel to allow servicing of switch components (e.g. indicia, optical components, etc.). The electrical contact structure of the switch 10 is not illustrated since it is irrelevant to the structure and operation of the present invention.

FIG. 2 illustrates the switch 10 of FIG. 1 provided with a guard device in accordance with the present invention. It will be noted that the conventional switch mounting screws 14 are reversed such that the threads thereof extend outwardly from the face of panel 12. Since switches of this type typically are mounted with two opposed screws 14, two additional guard mounting screws 18 (only one being visible) are inserted from beneath the panel 10 such that the threaded ends thereof also extend outwardly from the face of panel 10. Acylindrical guard 20 having an outside diameter slightly larger than the spacing between opposed screws 14 is provided at its lower end with four spaced apart flattened areas 22 which register with the four screws 14 and 18. The distance between opposed flattened areas 22 is slightly less than the spacing between the opposed screws 14 such that the guard 20 may be fitted into the nest formed by the screw threads. By rotating the guard 20 the round portion of the cylinder is wedged against the four screws locking it into position about the switch 10.

FIGS. 3A and 3B are top views of the arrangement of FIG. 2 wherein the installation and removal of the guard 20 is more clearly illustrated. It will be seen that the guard 20 is inserted with the flattened areas 22 in register with the screws 14 and 18. In FIG. 3B the guard 20 has been rotated counter clockwise such that the rounded surface of the cylinder is wedged against the threads of screws 14 and 18. The installation of the guard 20 does not impede the intentional actuation of the protected switch 10, however, it will be apparent that the danger of inadvertant actuation is substantially reduced. Installation and removal of the guard 20 requires only that it be twisted in one direction or the other and the upper portion may be suitably knurled as illustrated at 24 in FIG. 2 to facilitate this operation. Thus when a switch requires servicing from the front of the panel 12 the guard may be conveniently removed for this purpose.

The present invention has been described for the purposes of illustration assuming the protected switch to be mounted in a panel by two opposed screws, thus indicating a necessity for the two additional guard mounting screws. If, however, the switch were to be mounted with three or more screws a guard having a corresponding arrangement of flattened areas could be used without the requirement of any additional guard mounting screws. The invention is also illustrated with a push type switch. however, its application will be seen to extend to other types of switches as well. Finally, although the flattened areas of the guard are illustrated as being on the exterior surface thereof, they may also be disposed on the interior surface without departing from the principle of the invention.

From the preceding description it will be seen that the applicant has provided a new and novel guard device for preventing the inadvertent operation of electrical switches whereby the objectives set forth hereinabove are efficiently attained. Since certain changes in the above-described construction will occur to those skilled in the art without departure from the scope of the invention it is intended that all matter set forth in the foregoing description or shown in the appended drawings shall be interpreted as illustrative and not in a limiting sense.

Having described what is new and novel and desired to secure by Letters Patent, what is claimed is:

1. A switch guard for preventing the inadvertant operation of electrical switches mounted in a supporting panel by a plurality of means extending from the face of said panel and having an actuator extending from the face of said panel, said switch guard comprising a hollow, substantially cylindrical member having an inner diameter greater than the dimension of said switch actuator, an outer diameter greater than the distance between said switch mounting means, a

length which is greater than the distance by which said switch actuator extends from said panel, and having a plurality of spaced apart flattened portions proximate one end thereof and arranged such as to register with said plurality of switch mounting means such that upon rotation said cylindrical member engagessaid switch mounting means is retained in position about said switch actuator.

2. A device as recited in claim 1 wherein said flattened portions are disposed in the outer surface of said cylindrical member.

3. A device as recited in claim 1 further including a plurality of guard mounting means extending from the face of said panel and arranged with respect to said switch mounting means such as to form a nest into which said cylindrical member is fitted with said flattened portions thereof in register with each of said guard and switch mounting means.

4. A device as rectied in claim 1 wherein I said switch mounting means comprise screws having the threaded portions thereof extending from the face of said panel.

a a: t 

1. A switch guard for preventing the inadvertant operation of electrical switches mounted in a supporting panel by a plurality of means extending from the face of said panel and having an actuator extending from the face of said panel, said switch guard comprising a hollow, substantially cylindrical member having an inner diameter greater than the dimension of said switch actuator, an outer diameter greater than the distance between said switch mounting means, a length which is greater than the distance by which said switch actuator extends from said panel, and having a plurality of spaced apart flattened portions proximate one end thereof and arranged such as to register with said plurality of switch mounting means such that upon rotation said cylindrical member engages said switch mounting means is retained in position about said switch actuator.
 2. A device as recited in claim 1 wherein said flattened portions are disposed in the outer surface of said cylindrical member.
 3. A device as recited in claim 1 further including a plurality of guard mounting means extending from the face of said panel and arranged with respect to said switch mounting means such as to form a nest into which said cylindrical member is fitted with said flattened portions thereof in register with each of said guard and switch mounting means.
 4. A device as rectied in claim 1 wherein said switch mounting means comprise screws having the threaded portions thereof extending from the face of said panel. 